Musnad Ahmad 5:378

Hushaym narrated to us, Isma’il ibn Salim narrated to us, from al-Sha’bi, who said: "A married adulterer was brought to Ali, so he flogged him one hundred [lashes] on Thursday, then he stoned him on Friday. It was said to him: 'Have you combined two punishments upon him?' He said: 'I flogged him by the Book of Allah, and I stoned him by the Sunnah of the Messenger of Allah, may Allah bless him and grant him peace.'" *** Abdullah narrated to us, my father narrated to me, Hushaym and Abu Ibrahim al-Mu’aqqib narrated to us, they said: Hushaym narrated to us, Husayn informed us, from al-Sha’bi, who said: "A freedwoman of Sa’id ibn Qays, who was married, was brought to Ali, and she had committed adultery. He said: So he struck her one hundred [lashes], then he stoned her. Then he said: 'I flogged her by the Book of Allah, and I stoned her by the Sunnah of the Messenger of Allah, may Allah bless him and grant him peace.'"